1. Field of Invention
The invention relates to a light emitting element and module, and in particular, to an LED (light emitting diode) light emitting element and light emitting module that does not need the wire bonding.
2. Related Art
The purpose of packaging an LED (light emitting diode) is to ensure the correct electrical connection of the LED chip, and to protect the LED chip from being influenced by mechanical, thermal, humidity, and other external factors. A state-of-the-art LED packaging has diverse types in view of different applications, product appearances and sizes, heat dissipation solutions, and illumination effects.
The conventional LED packaging technology requires a package body to bear an LED die. However, since the package body has a smaller heat transfer coefficient, and the heat transfer coefficients of the LED die and the packaging body are different, the device may be damaged easily in a high-temperature environment.
Furthermore, the conventional manufacturing process of packaging connects an LED to a substrate or a lead frame by wire bonding. Such a wire bonding process connects the two ends of a gold or aluminum wire having a diameter of 25 μm to the chip and the substrate or the lead frame, respectively, by thermo-compression bonding, ultrasonic bonding or ultrasonic-assisted thermo-compression bonding. However, this process suffers from the problems of insufficient adhesion three of the wires on the die electrodes and the breakage of the wires. Moreover, the amount of light emitted by the LED is reduced due to the shield effect of the wires.
Another conventional packaging technique is flip-chip bonding, in which the die of a flip-chip LED is flipped and is bonded on a substrate directly without wire bonding. Since the light emitted is not shielded by the wires and electrodes, the light-emitting efficiency of the LED can be enhanced, while the heat conducting effect is also better. However, since the flip-chip LED is bonded to the substrate by die bonding, the sizes of the PN electrodes are limited to the size of the LED die. Therefore, die-bonding machine of high precision must be used during die-bonding, which the cost is expensive.
Therefore, it is desired to provide a light emitting element and a light emitting module that does not need wire bonding, does not need a packaging body, and is easy to be bonded, to solve the problems in the conventional art mentioned above.